Screen printing apparatus

ABSTRACT

The screen printing apparatus includes two screen printers  11 A and  11 B each including a substrate introduction portion  12  by which a substrate  4  is introduced from the upstream side of the component mounting line  3,  a printing portion  13  which performs a screen printing to the introduced substrate  4,  a substrate discharge portion  14  by which the substrate  4  subjected to the screen printing is discharged to the downstream side, and a substrate moving stage  15  which receives the introduced substrate  4  so as to position the substrate  4  with respect to the printing portion  13  and to move the substrate  4  subjected to the screen printing to the substrate discharge portion  14.  The two substrate introduction portions  12,  the two printing portions  13,  and the two substrate discharge portions  14  are arranged symmetrically to each other with respect to a perpendicular symmetrical plane S extending in a transportation direction of the substrate  4  in the component mounting line  3,  respectively. Each printing portion  13  is provided at a position further from the perpendicular symmetrical plane S than the substrate discharge portion  14.

TECHNICAL FIELD

The present invention relates to a screen printing apparatus which ismounted to a component mounting line to perform a screen printing to asubstrate introduced from the upstream side and to discharge thesubstrate to the downstream side of the component mounting line.

BACKGROUND ART

A screen printing apparatus is mounted to a component mounting linetogether with a component mounting apparatus or an attachment apparatusto perform a screen printing using cream solder or conductive paste to asubstrate introduced from the upstream side and to discharge thesubstrate to an apparatus provided on the downstream side of thecomponent mounting line. In general, the screen printing apparatus isdisposed on the upstream side of the component mounting apparatus andthe substrate subjected to the screen printing is directly or indirectlytransferred from a substrate discharge portion of the screen printingapparatus to a substrate transportation path of the component mountingapparatus. The component mounting apparatus mounts components to thesubstrate introduced from the screen printing apparatus, and dischargesthe substrate to an apparatus provided on the downstream side via thesubstrate transportation path.

Incidentally, among recent component mounting apparatuses, there is acomponent mounting apparatus in which two parallel substratetransportation paths are provided and the component mounting operationis simultaneously carried out by two component mounting lines via thetwo substrate transportation paths. Likewise, when the componentmounting apparatus includes two substrate transportation paths, thesubstrate discharged from the substrate discharge portion of the screenprinting apparatus is distributed to the two substrate transportationpaths of the component mounting apparatus by a substrate distributingdevice provided between the component mounting apparatus and the screenprinting apparatus (JP-A-H04-129630).

However, in the component mounting apparatus having the two componentmounting lines, the component mounting operation may be carried out inthe different types of substrates (including a case carried out in thesame type of substrates but on different surfaces in addition to a casecarried out the different types of the substrates) at the same time aswell as the component mounting operation carried out in the same type ofsubstrates. In this case, since the screen printing apparatus cannotcontinuously perform the screen printing to the different types ofsubstrates, it is necessary to provide two screen printing apparatusesin parallel to each other at a position on the upstream side of thecomponent mounting apparatus. However, since the interval between thetwo substrate transportation paths constituting the component mountingapparatus is very narrow, it is very difficult to provide two screenprinting apparatuses in parallel so that the substrate dischargeportions of the screen printing apparatuses are opposed to the twosubstrate transportation paths of the component mounting apparatus.

Additionally, instead of the above-described technique, it may besupposed that two types of mask plates are provided at a position aboveone substrate transportation path constituting the screen printingapparatus so as to be disposed in a line in a direction in which thesubstrate transportation path extends (JP-A-2000-168040), therebyperforming the different types of screen printings to the substrate onthe substrate transportation path. However, since the different types ofmasks are provided in serial to the one substrate transportation path ofthe screen printing apparatus, it is necessary to provide a complexsubstrate supply system to the substrate transportation path so as tosupply the different substrates alternatively or once in severalsubstrates.

DISCLOSURE OF THE INVENTION

Therefore, an object of the invention is to provide a screen printingapparatus capable of simultaneously performing the screen printing tothe different types of substrates without the complex substrate supplysystem.

According to the first aspect of the invention, there is provided ascreen printing apparatus mounted to a component mounting line, theapparatus comprising:

two screen printers each including a substrate introduction portion bywhich a substrate is introduced from an upstream side of the componentmounting line;

a printing portion which performs a screen printing to the substrateintroduced by the substrate introduction portion;

a substrate discharge portion by which the substrate subjected to thescreen printing by the printing portion is discharged to a downstreamside of the component mounting line; and

a substrate moving stage which receives the substrate introduced by thesubstrate introduction portion to position the substrate with respect tothe printing portion and to move the substrate subjected to the screenprinting by the printing portion to the substrate discharge portion,

wherein the two substrate introduction portions, the two printingportions, and the two substrate discharge portions of the two screenprinters are arranged symmetrically to each other with respect to aperpendicular symmetrical plane extending in a substrate transportationdirection of the component mounting line, respectively, and

wherein the printing portion of each screen printer is provided at aposition further from the perpendicular symmetrical plane than thesubstrate discharge portion.

The second aspect of the invention provides the screen printingapparatus described in the first aspect of the invention, wherein thetwo substrate discharge portions are provided at a position opposed totwo parallel substrate transportation paths formed in a componentmounting apparatus provided on the downstream side of the componentmounting line in the substrate transportation direction.

According to the invention, since the screen printing apparatus includesthe two screen printers each including the substrate introductionportion, the printing portion, the substrate discharge portion, and thesubstrate moving stage so as to independently perform the screenprinting, it is possible to simultaneously perform the screen printingto the different types of substrates. Additionally, even when thecomponent mounting apparatus provided on the downstream side includestwo substrate transportation paths, it is possible to transport thesubstrates subjected to the screen printing to the substratetransportation paths without a substrate distributing device.

Since the two substrate introduction portions, the two printingportions, and the two substrate discharge portions constituting the twoscreen printers are respectively formed at a position symmetrical toeach other with respect to the perpendicular symmetrical plane extendingin the substrate transportation direction in the component mountingline, it is easy to arrange the respective portions of the screenprinters. Additionally, since each printing portion of the screenprinters is provided at a position further from the perpendicularsymmetrical plane than the substrate discharge portion, even when theinterval between the two substrate discharge portions cannot be set tobe narrow so as to correspond to the interval between the two substratetransportation paths constituting the component mounting apparatus asthe apparatus provided on the downstream side, it is possible to arrangethe two printing portions at a position symmetrical to each other so asnot to interfere with each other.

Since the two screen printers are provided in parallel to each other andeach includes the exclusive substrate introduction portion, when thescreen printing is simultaneously performed to the different types ofsubstrates, the type of the substrate may be changed between the twoscreen printers and the same type of substrate may be continuouslysupplied to each of the screen printers. Accordingly, unlike theconventional art, it is not necessary to provide such a complexsubstrate supply system that the different type substrates are suppliedalternately or once in several other substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a component mounting line according to anembodiment of the invention.

FIG. 2 is a front view showing a screen printing apparatus according tothe embodiment of the invention.

FIG. 3 is a front view showing a screen printer of the screen printingapparatus according to the embodiment of the invention.

FIG. 4 is a side view showing the screen printer of the screen printingapparatus according to the embodiment of the invention.

FIGS. 5A and 5B are explanatory views showing an operation of the screenprinter of the screen printing apparatus according to the embodiment ofthe invention.

FIGS. 6A to 6F are explanatory views showing the operation of the screenprinter of the screen printing apparatus according to the embodiment ofthe invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the invention will be described withreference to the accompanying drawings. FIG. 1 is a top view showing acomponent mounting line according to an embodiment of the invention.FIG. 2 is a front view showing a screen printing apparatus according tothe embodiment of the invention. FIG. 3 is a front view showing a screenprinter of the screen printing apparatus according to the embodiment ofthe invention. FIG. 4 is a side view showing the screen printer of thescreen printing apparatus according to the embodiment of the invention.FIGS. 5A and 5B are explanatory views showing an operation of the screenprinter of the screen printing apparatus according to the embodiment ofthe invention. FIGS. 6A to 6F are explanatory views showing theoperation of the screen printer of the screen printing apparatusaccording to the embodiment of the invention.

In FIG. 1, a screen printing apparatus 1 is mounted to a componentmounting line 3 together with a plurality of component mountingapparatuses 2 or an attachment apparatus (not shown), and performs ascreen printing to a substrate 4 introduced from the upstream side so asto subsequently discharge the substrate to the component mountingapparatuses 2 provided on the downstream side.

In FIGS. 1 and 2, the screen printing apparatus 1 includes two screenprinters 11A and 11B provided on a base 10. Each of the two screenprinting apparatuses 11A and 11B includes a substrate introductionportion 12 by which the substrate 4 is introduced from the upstream sideof the component mounting line 3 onto the base 10, a printing portion 13which performs a screen printing to the substrate 4 introduced by thesubstrate introduction portion 12 onto base 10, a substrate dischargeportion 14 by which the substrate 4 subjected to the screen printing bythe printing portion 13 is discharged to the downstream side of thecomponent mounting line 3, and a substrate moving stage 15 whichreceives the substrate 4 introduced by the substrate introductionportion 12 to position the substrate 4 with respect to the printingportion 13 and to move the substrate 4 subjected to the screen printingby the printing portion 13 to the substrate discharge portion 14.

The substrate introduction portion 12 constituting each of the screenprinters 11A and 11B is provided with a substrate introduction path 12 ahaving two parallel transportation rails extending in a transportationdirection (X-axis direction) of the substrate 4 in the componentmounting line 3. The substrate discharge portion 14 constituting each ofthe screen printers 11A and 11B is provided with a substrate dischargepath 14 a having two parallel transportation rails extending in anX-axis direction in the same manner.

As shown in FIGS. 1 and 2, the two substrate introduction portions 12(the substrate introduction paths 12 a provided in the substrateintroduction portion 12) and the two substrate discharge paths 14 (thesubstrate discharge paths 14 a provided in the substrate discharge path14) constituting the two screen printers 11A and 11B are respectivelyarranged symmetrically to each other with respect to a perpendicularsymmetrical plane S extending in an X-axis direction corresponding tothe transportation direction of the substrate 4 in the componentmounting line 3. Additionally, the two printing portions 13 are arrangedsymmetrically to each other with respect to the perpendicularsymmetrical plane S, and each horizontal distance D of the printingportions 13 from the perpendicular symmetrical plane S is set to belarger than each horizontal distance d of the substrate dischargeportions 14 from the perpendicular symmetrical plane S (FIG. 2). Thatis, in the respective screen printers 11A and 11B, the printing portions13 are positioned further from the perpendicular symmetrical plane Sthan the substrate discharge portions 14.

In FIGS. 3 and 4, the substrate moving stage 15 constituting each of thescreen printers 11A and 11B includes an Y-axis stage 21 which is movableon the base in a horizontal direction (Y-axis direction) perpendicularto an X-axis direction, an X-axis stage 22 which is movable on theY-axis stage 21 in an X-axis direction, a θ-stage 23 which is movable onthe X-axis stage 22 in a circumferential direction of a vertical axis, abase plate 24 which is fixed to the upper surface of the O-stage 23, afirst elevation plate 25 which is elevatable with respect to the baseplate 24, and a second elevation plate 26 which is elevatable withrespect to the first elevation plate 25.

A plurality of guide members 27 is uprightly formed in the upper surfaceof the first elevation plate 25, and two parallel transportation rails28 are supported to the upper end portions of the plurality of guidemembers 27 so as to extend in parallel in an X direction correspondingto the transportation direction of the substrate 4. A substrate supportmember 29 is provided in the upper surface of the second elevation plate26, and a pair of clamp members 30 is provided above the twotransportation rails 28. The two transportation rails 28 are provided atthe same interval therebetween in the same manner as the twotransportation rails constituting the substrate introduction path 12 aand the two transportation rails constituting the substrate dischargepaths 14 a.

The Y-axis stage 21 is screwed to a feed screw (not shown) rotationallydriven by a Y-axis stage driving motor 21 a. When a control unit 31provided in the base 10 controls the Y-axis stage driving motor 21 a torotate, the Y-axis stage 21 is moved by the feed screw in a Y-axisdirection. The X-axis stage 22 is screwed to a feed screw (not shown)rotationally driven by an X-axis stage driving motor 22 a. When thecontrol unit 31 controls the X-axis stage driving motor 22 a to rotate,the X-axis stage 22 is moved by the feed screw in an X-axis direction.The θ-stage 23 is connected to a θ-stage driving motor (not shown). Whenthe control unit 31 controls the θ-stage driving motor to rotate, theθ-stage 23 rotates in a circumferential direction of the vertical axis.

In FIGS. 3 and 4, a first elevation motor 25 a is fixed to the baseplate 24, and a first feed screw 25 b is screwed to the first elevationplate 25. A first belt 25 c is suspended on a driving shaft of the firstelevation motor 25 a and the first feed screw 25 b. When the controlunit 31 controls the first elevation motor 25 a to rotate, the firstfeed screw is rotated by the first belt 25 c, and the first elevationplate 25 is elevated by the first feed screw 25 b. Additionally, asecond elevation motor 26 a is fixed to the first elevation plate 25,and a second feed screw 26 b is screwed to the second elevation plate26. A second belt 26 c is suspended on a driving shaft of the secondelevation motor 26 a and the second feed screw 26 b. When the controlunit 31 controls the second elevation motor 26 a to rotate, the secondfeed screw 26 b is rotated by the second belt 26 c, and the secondelevation plate 26 is elevated by the second feed screw 26 b.

The clamp members 30 are connected to a clamp cylinder 30 a fixed to oneof the guide members 27. When the control unit 31 controls the clampcylinder 30 a to project or retract, the clamp members 30 on thetransportation rails 28 are opened or closed in a Y-axis direction.Accordingly, when the second elevation plate 26 is elevated in a statewhere the substrate 4 is located at a position just above the substratesupport member 29, and the clamp members 30 are closed to clamp thesubstrate 4 in a state where the substrate support member 29 comes intocontact with the lower surface of the substrate 4, it is possible to fixthe substrate 4 onto the transportation rails 28.

In FIGS. 3 and 4, the printing portion 13 includes a mask plate 41 whichis provided above the substrate moving stage 15, a squeegee head 42which is provided above the mask plate 41, a squeegee head movingmechanism 43 which moves the squeegee head 42 in a horizontal plane, acamera 44 which is provided between the substrate moving stage 15 andthe mask plate 41, and a camera moving mechanism 45 which moves thecamera 44 in a horizontal plane.

The four sides of the mask plate 41 are supported by a rectangular maskframe 41 a so as to be horizontal at a position above the transportationrails 28. A plurality of pattern holes (not shown) is formed in the maskplate in accordance with the position or the shape of an electrode (notshown) of the substrate 4.

In FIG. 4, two vertical frames 46 are uprightly formed in the base 10 soas to be opposed to each other in an X-axis direction, and a first guiderail 47 is provided in each upper end portion of the vertical frames 46so as to extend in a Y-axis direction. A block member 49, having aslider 48 formed on the lower surface, is provided in the pair of firstguide rails 47 so as to be movable along the first guide rails 47 in aY-axis direction. A movement plate 50 is suspended on the both blockmembers 49 in an X-axis direction.

The squeegee head 42 is fixed to the center portion of the movementplate 50 in an X-axis direction so as to be movable at a position abovethe mask plate 41 together with the movement plate 50 in a Y-axisdirection. In FIGS. 3 and 4, the squeegee head 42 includes a pair ofsqueegees which extends in an X-axis direction so as to be opposed toeach other in a Y-axis direction and a squeegee elevating cylinder 52which elevates each squeegee 51. The control unit 31 controls theoperation of the squeegee elevating cylinder 52.

The squeegee head moving mechanism 43 includes the vertical frames 46,the first guide rails 47, the sliders 48, the block members 49, and themovement plate 50. The movement plate 50 is screwed to a feed screw (notshown) rotationally driven by a squeegee head moving motor (not shown).When the control unit 31 controls the squeegee head moving motor torotate, the movement plate 50 on the first guide rails 47 is moved bythe feed screw in a Y-axis direction. Accordingly, it is possible toreciprocate the squeegees 51 mounted to the squeegee head 42 in a Y-axisdirection.

In FIG. 4, the camera moving mechanism 45 includes two second guiderails 53 which are provided in the upper end portions of the twovertical frames 46 so as to extend in a Y-axis direction, a cameraholding stage 54 which is suspended on the two second guide rails 53 soas to extend in an X-axis direction at a position between thetransportation rails 28 and the mask plate 41 and to be movable alongthe two second guide rails 53 in a Y-axis direction, and a camera stage55 (FIG. 3) which is movable along the camera holding stage 54 in anX-axis direction. The camera 44 is attached to the camera stage 55.

As shown in FIG. 3, the camera 44 includes a substrate recognizingcamera 44 a of which an imaging surface faces the downside and a maskrecognizing camera 44 b of which an imaging surface faces the upside.The control unit 31 controls the operation of the substrate recognizingcamera 44 a and the mask recognizing camera 44 b. The imaging resultobtained by the substrate recognizing camera 44 a and the maskrecognizing camera 44 b is input to the control unit 31.

The camera holding stage 54 is screwed to a feed screw (not shown)rotationally driven by a camera holding stage moving motor (not shown).When the control unit 31 controls the camera holding stage moving motorto rotate, the camera holding stage 54 is moved by the feed screw in aY-axis direction. Additionally, the camera stage 55 is screwed to a feedscrew (not shown) rotationally driven by a camera stage moving motor 55a (FIG. 3). When the control unit 31 controls the camera stage movingmotor 55 a to rotate, the camera stage 55 is moved by the feed screw inan X-axis direction. Accordingly, it is possible to move the camerastage 55 in a horizontal plane.

Next, a sequence of the screen printing which is performed to thesubstrate 4 by the screen printers 11A and 11B will be described withreference to FIGS. 5A and 5B. When the substrate 4 is introduced fromthe apparatus provided on the upstream side of the screen printingapparatus 1 in the component mounting line 3 to the substrateintroduction portion 12 of the screen printer 11A (or 11B), the controlunit 31 controls the operation of the substrate introduction path 12 aprovided in the substrate introduction portion 12 so that the substrate4 is introduced to the base 10 and the substrate 4 is again loaded fromthe substrate introduction path 12 a onto the transportation rails 28 ofthe substrate moving stage 15. When the substrate 4 is loaded again onthe transportation rails 28, the control unit 31 controls the operationof the transportation rails 28 so that the substrate 4 is introduced toa position just above the substrate support member 29 and the substrate4 is clamped on the transportation rails 28 in the above-describedsequences (FIG. 5A). Then, the camera stage 55 is moved in a horizontalplane so that the position of the substrate 4 is recognized by thesubstrate recognizing camera 44 a and the position of the mask plate 41is recognized by the mask recognizing camera 44 b. Also, the Y-axisstage 21, the X-axis stage 22, and the θ-stage 23 are moved so that theclamped substrate 4 is positioned with respect to a predeterminedposition just below the mask plate 41.

When the positioning operation of the substrate 4 ends, the control unit31 elevates the first elevation plate 25 with respect to the base plate24 so that the upper surface of the substrate 4 comes into contact withthe lower surface of the mask plate 41 and paste 56 such as cream solderor conductive paste is supplied from a dispenser (not shown) to theupper surface of the mask plate 41. Then, one squeegee elevatingcylinder 52 extends downward so that the lower edge of the squeegee 51attached to the squeegee elevating cylinder 52 comes into contact withthe upper surface of the mask plate 41.

When the lower edge of the squeegee 51 comes into contact with the uppersurface of the mask plate 41, the control unit 31 operates the squeegeehead moving mechanism 43 so that the whole portion of the movement plate50 is moved in a direction (Y-axis direction) parallel to a direction ofthe substrate 4 and the paste 56 is collected by the squeegee 51 in ascraping manner, thereby transferring the paste 56 to electrodes of thesubstrate 4 via the pattern hole of the mask plate 41 (FIG. 5B).

When the paste 56 is transferred to the substrate 4, the control unit 31moves down the first elevation plate 25 with respect to the base plate24 and moves the upper surface of the substrate 4 and the lower surfaceof the mask plate 41 to be away from each other. Then, the Y-axis stage21 (the X-axis stage 22 and the θ-stage 23 depending on the case) ismoved in a Y-axis direction so that the transportation rails 28 arepositioned with respect to the substrate discharge path 14 a.Accordingly, the substrate 4 is moved to the substrate discharge portion14.

When the substrate 4 is moved to the substrate discharge portion 14, thecontrol unit 31 opens the clamp members 30 so that the operation of thetransportation rails 28 and the substrate discharge path 14 a iscontrolled to transport the substrate 4 from the substrate dischargeportion 14 to the component mounting apparatuses on the downstream side.Accordingly, the screen printing performed to the substrate 4 by thescreen printers 11A and 11B ends.

Here, a configuration of each component mounting apparatus 2 will besimply described. As shown in FIG. 1, the component mounting apparatus 2includes two substrate transportation paths 62 a and 62 b having twoparallel transportation rails provided on a base 61 so as to extend inan X-axis direction, the two substrate transportation paths 62 a and 62b being in parallel to each other. A Y-axis table 63 is provided in thebase 61 so as to extend in a Y-axis direction, and two X-axis tables 64are provided in the Y-axis table 63 so as to extend in an X-axisdirection, one end portion being supported to the Y-axis table 63. Amovement table 65 is provided in each X-axis table 64 so as to bemovable along the X-axis table 64 (in an X-axis direction).

Since each X-axis table 64 is movable along the Y-axis table 63 in aY-axis direction and each movement table 65 is movable along the X-axistable 64 in an X-axis direction, each movement table 65 is capable ofmoving to an arbitrary position in the horizontal plane in terms of thecombination of the movement operation of the X-axis table 64 and theself movement operation of the movement table 65. Additionally, aplurality of parts feeders 66 are provided on both sides of the base 61in a Y-axis direction so as to be arranged in an X-axis direction.

Each movement table 65 is provided with a transfer head 67 having aplurality of adsorption nozzles (not shown) extending downward. In termsof the movement of the movement table 65 and the adsorption operation ofthe adsorption nozzles, the components (not shown) are picked up fromthe parts feeder 66 and the components (not shown) are loaded onto thesubstrate 4 which is introduced from the screen printing apparatus 1 tothe substrate transportation paths 62 a and 62 b to be therebypositioned with respect to a predetermined position thereon. Then, afterending the operation in which the components are loaded on the substrate4, the substrate 4 is introduced to an apparatus provided on thedownstream side via the substrate transportation paths 62 a and 62 b.

Here, the two substrate discharge paths 14 a constituting the screenprinting apparatus 1 are provided at a position opposed to the twosubstrate transportation paths 62 a and 62 b constituting the componentmounting apparatus 2 in the transportation direction (X-axis direction).That is, the interval between the two substrate discharge portions 14 ofthe screen printing apparatus 1 is set so as to correspond to theinterval between the two substrate transportation paths 62 a and 62 bconstituting the component mounting apparatus 2 provided on thedownstream side.

Next, a sequence in which the screen printing is simultaneouslyperformed to different types (two types) of substrates (denoted byreference numerals 4 a and 4 b) by the screen printing apparatus 1according to this embodiment will be described with reference to FIGS.6A to 6F. Here, an example of “different types” includes a case in whichthe same type of substrate 4 has different surfaces in addition to acase in which the type of the substrate 4 is different.

When the substrate 4 a is introduced from the apparatus provided on theupstream side of the screen printing apparatus 1 in the componentmounting line 3 to the substrate introduction portion 12 of the screenprinter 11A, the control unit 31 loads again the substrate 4 a onto thetransportation rails 28 of the substrate movement stage 15 so as to bepositioned with respect to the printing portion 13, thereby performingthe screen printing to the substrate 4 a (FIGS. 6A and 6B).

When ending the screen printing performed to the substrate 4 a by thescreen printer 11A, the control unit operates the substrate moving stage15 of the screen printer 11A so that the substrate 4 a is moved to thesubstrate discharge portion 14 (FIG. 6C) and the substrate 4 a isdischarged from the substrate discharge portion 14 (FIG. 6D). Thesubstrate 4 a discharged from the substrate discharge portion 14 of thescreen printer 11A is transferred to the substrate transportation path62 a opposed to the substrate discharge portion 14 of the screen printer11A, among the two substrate transportation paths 62 a and 62 bconstituting the component mounting apparatus 2 on the downstream side.

On the other hand, for the mean time, in the screen printer 11B, thesubstrate 4 b introduced by the substrate introduction portion 12 isloaded again onto the transportation rails 28 of the substrate movingstage 15 so as to be positioned with respect to the printing portion 13,thereby performing the screen printing to the substrate 4 b (FIGS. 6Band 6C).

When ending the screen printing performed to the substrate 4 b by thescreen printer 11B, the control unit operates the substrate moving stage15 of the screen printer 11B so that the substrate 4 b is moved to thesubstrate discharge portion 14 (FIG. 6D) and the substrate 4 b isdischarged from the substrate discharge portion 14 (FIG. 6E). Thesubstrate 4 b discharged from the substrate discharge portion 14 of thescreen printer 11B is transferred to the substrate transportation path62 a opposed to the substrate discharge portion 14 of the screen printer11B, among the two substrate transportation paths 62 a and 62 bconstituting the component mounting apparatus 2 on the downstream side.

For the mean time, in the screen printer 11A, the substrate 4 aintroduced by the substrate introduction portion 12 is loaded again ontothe transportation rails 28 of the substrate moving stage 15 so as to bepositioned with respect to the printing portion 13, thereby performingthe screen printing to the substrate 4 a (FIGS. 6C and 6D). Then, whenending the screen printing performed to the substrate 4 a, the substratemoving stage of the screen printer 11A is operated so that the substrate4 a is moved to the substrate discharge portion (FIG. 6E) and thesubstrate 4 a is discharged from the substrate discharge portion 14(FIG. 6F). Hereinafter, by repeatedly performing the above-describedoperations, it is possible to simultaneously perform the screen printingto the different types of substrates 4 a and 4 b.

As described above, since the screen printing apparatus 1 according tothis embodiment includes the two screen printers (the screen printers11A and 11B) each including the substrate introduction portion 12, theprinting portion 13, the substrate discharge portion 14, and thesubstrate moving stage 15 so as to independently perform the screenprinting, it is possible to simultaneously perform the screen printingto the different types of substrates. Like this embodiment, even whenthe component mounting apparatus 2 on the downstream side includes twosubstrate transportation paths 62 a and 62 b, it is possible totransport the substrate 4 (substrates 4 a and 4 b) subjected to thescreen printing to the substrate transportation paths 62 a and 62 bwithout a substrate distributing device.

Since the two substrate introduction portions 12, the two printingportions 13, and the two substrate discharge portions 14 constitutingthe two screen printers 11A and 11B are respectively formed at aposition symmetrical to each other with respect to the perpendicularsymmetrical plane S extending in the transportation direction (X-axisdirection) of the substrate 4 in the component mounting line 3, it iseasy to arrange the respective portions of the screen printers 11A and11B. Additionally, since each printing portion 13 of the screen printers11A and 11B is provided at a position further from the perpendicularsymmetrical plane S than the substrate discharge portion 14, even whenthe interval between the two substrate discharge portions 14 cannot beset to be narrow so as to correspond to the interval between the twosubstrate transportation paths 62 a and 62 b constituting the componentmounting apparatus 2 as the apparatus provided on the downstream side,it is possible to arrange the two printing portions 13 at a positionsymmetrical to each other so as not to interfere with each other.

Since the two screen printers 11A and 11B are provided in parallel toeach other and each includes the exclusive substrate introductionportion 12, when the screen printing is simultaneously performed to thedifferent types of substrates 4, the type of the substrate 4 may bechanged between the two screen printers 11A and 11B and the same type ofsubstrate 4 may be continuously supplied to each of the screen printers11A and 11B. Accordingly, unlike the conventional art, it is notnecessary to provide a complex substrate supply system in which thedifferent types of substrates are supplied alternately or at intervals.

While the exemplary embodiment of the invention has been described, theinvention is not limited to the above-described embodiment. For example,although the above-described embodiment has a configuration in which thesubstrate 4 discharged from the two substrate discharge portions 14constituting the screen printing apparatus 1 is directly transferred tothe two substrate transportation paths 62 a and 62 b constituting thedownstream component mounting apparatus 2, the substrate 4 may beindirectly transferred between the screen printing apparatus 1 and thecomponent mounting apparatus 2 by providing an additional substratetransportation path between the screen printing apparatus 1 and thecomponent mounting apparatus 2.

Further, by allowing the additional substrate transportation path to bemovable in a Y-axis direction, it is possible to selectively distributethe substrate 4, discharged from one of the two substrate dischargeportions 14 of the screen printing apparatus 1, to one of the twosubstrate transportation paths 62 a and 62 b of the component mountingapparatus 1.

Furthermore, although the above-described embodiment has a configurationin which the substrate introduction portion 12 is provided with thesubstrate introduction path 12 a having two parallel transportationrails and the substrate discharge portion 14 is provided with thesubstrate discharge path 14 a having two parallel transportation rails,when the two transportation rails 28 constituting the substrate movingstage 15 extend in the transportation direction (X-axis direction) ofthe substrate 4 in the component mounting line 3, the transportationrails 28 of the substrate moving stage 15 may serve as the substrateintroduction path 12 a and the substrate discharge path 14 a.Accordingly, in such a configuration, it is not necessary to provide thesubstrate introduction path 12 a and the substrate discharge path 14 a.

It is possible to provide the screen printing apparatus capable ofsimultaneously performing the screen printing to the different types ofsubstrates without the complex substrate supply system.

1. A screen printing apparatus mounted to a component mounting line, theapparatus comprising: two screen printers each including a substrateintroduction portion by which a substrate is introduced from an upstreamside of the component mounting line; a printing portion which performs ascreen printing to the substrate introduced by the substrateintroduction portion; a substrate discharge portion by which thesubstrate subjected to the screen printing by the printing portion isdischarged to a downstream side of the component mounting line; and asubstrate moving stage which receives the substrate introduced by thesubstrate introduction portion to position the substrate with respect tothe printing portion and to move the substrate subjected to the screenprinting by the printing portion to the substrate discharge portion,wherein the two substrate introduction portions, the two printingportions, and the two substrate discharge portions of the two screenprinters are arranged symmetrically to each other with respect to aperpendicular symmetrical plane extending in a substrate transportationdirection of the component mounting line, respectively, and wherein theprinting portion of each screen printer is provided at a positionfurther from the perpendicular symmetrical plane than the substratedischarge portion.
 2. The screen printing apparatus according to claim1, wherein the two substrate discharge portions are provided at aposition opposed to two parallel substrate transportation paths formedin a component mounting apparatus provided on the downstream side of thecomponent mounting line in the substrate transportation direction.